I’ve read that electric locomotives (some people object to referring to them as locomotives) can develop far more horspower than a diesel electric…10,000 - 15000 hp out of one unit. Wouldn’t that make them very “slippery”? I’ve read that B-B diesels of 3000 hp and up are slippery…so these electrics would be quite tempermental on the throttle…no?
I would imagine with the new computer controls, the locomotive builders can more than likely control that problem. R. Staller
I’m out my depth, but I wouldn’t expect the engineer to apply all the potential HP to the rail head upon startup, or during hard pulling at about any speed. I know the GG1 was very heavy, and could develop something near 8000 HP for a short period.
Ramming the throttle forward on any locomotive/traction unit would be an invitation to a spin below about 15 mph, give or take load/speed/grade/gearing…
-Crandell
As with any locomotive it is controlled by weight on drivers, weight of unit and of train, horsepower at start, tractive effort or adhesion, sand, throttle control (its own values vs values of engineer/operator), whatever new electronics or control devices are added to the mix, and the engineer/operator himself.
That’s one reason for the ‘objection’ - the electric isn’t really generating the power, but instead drawing power through the catenary from wherever it is generated . . . and I noticed you used the verb ‘develop’, not ‘generate’ or ‘produce’, too.
I’ve not seen any claim for 15,000 HP out of a single unit, but even the old 2-C+C-2 GG1 had a short-term rating of 8,000 to 9,000 HP - sources vary on that - and the AEM7/ ALP44 ‘Sewdish meatball’ / ‘toaster’ series that inhabit the NorthEast Corridor are rated at 7,000 HP - on only B-B trucks, no less ! So yes, as a general statement electrics are capable of very high HP output per unit, much higher than any single diesel-electric - at least for short-term ratings of like 5 mins. to 1 hour - mainly because the electric’s power supply is not limited by whatever prime mover engine that they have carry around with them.
This is a potentially long and complicated subject, which boils down to, ‘‘It depends’’ on how well the electric is matched to the service in which it is being used, and the skill of the engineman. i’ve never heard or read that the GG1 was view
I imagine just like diesel electric AC’s of today that if one axel over loads, it will reduce or cut off power to that axel until it regains traction.
Mabey not?
Justin
The HHP8 (High Horse Power 8,000) used by Amtrak and MARC develops 8,000hp and 71,240 pounds Tractive Effort. (the cover of “Trains Magazine” for November, Photoshopped into Union Pacific colors)
The Acela is powered to 150 mph by 2 locomotives, 6,000hp each, one on each end.
What nobody has mentioned is the reason for all of this horsepower being available; maybe since it is so obvious. A diesel driving a generator only possesses the horsepower of the prime mover, while an electric essentially has the entire electric grid as a prime mover. Most electrical machinery, transformers as well as motors, has significant short term overload capability – just don’t melt them. Yes, some components, especially semiconductors, have hard limits on maximum amps.
I’m a retired electrical engineer with some background in power systems, and I occasionally post on “Live Diesel.”
---- Doug.
Also in the reason column is the reason why so much power is needed. As stated above speed is the issue, to keep accelerating you need loads and loads of power. And linked is the fact that air resistance increases with the square of the velocity. Double the speed; quadruple the resistance, which means loads of power is needed plus some pretty clever aerodynamics.
10,000hp short term rating in a light electric locomotive of about 90tons is good for accelertating a passenger train from 80mph to 140mph of maybe 10 coahes or 400tons.
These are just rough estimated numbers to make a point without exagerating, but similar to modern European Intercity trains.
Here is a link to a modern heavy-haul European electric locomotive. 10.8 MW of power ( 14,475hp) for each unit, each unit weighs 180 tonnes (198 US tons). These locomotives operate normally as a back to back pair. They can produce 600kN of TE (135,000lbs) at 19.9 mph.
They are used to haul Iron Ore trains in Norway and Sweden, north of the Arctic Circle.
The link suggests 10.8 MW total for the pair-- i.e 600 kN per unit at 32.4 km/hr = 5400 kW per unit.
Suppose we’re hoping for 1 mph/sec acceleration at 100 mph with a 490-short-ton-total train-- turns out we would need at least 14000 hp at the wheelrims. People like to scoff at the “overpowered” Acela, but if you want snappy acceleration at 100+ mph there’s no such thing as too much power.
1mph/sec accel at 100 mph IS pretty snappy!
Which is broadly what the newer French TGV sets have. 8800 kw = 11,792hp. Unladen weight 359 tons giving a power to weight ration of 32.8hp per ton (obviously a little less fully loaded). The calculation above has a power to weight ration of 28.6hp per ton.
As timx nearly said there’s no such thing as too much power at 150mph!
After checking elsewhere, you are correct. That makes these Chinese built, using Siemens technology locomotives the most powerful single units, at 9.6 MW. No information on TE. They are intended for freight use. Scroll down the page a little.